Doctor Who: What Happened To Every Companion?

Words cannot express just how much David Tennant's era did for Doctor Who. While the eras after it would reap the benefits from it bringing Doctor Who fully into the mainstream, the 10th era is what got the world at large to discover Doctor Who. And while much of that comes from The Doctor himself, it has the companions to thank just as much.

10 inherited the companions from 9, and even added Rose's ex-boyfriend Mickey Smith. Mickey would be the first one to leave. After traveling with The Doctor and generally feeling underappreciated, Mickey found his calling when the group were sent to an alternate universe where Mickey leads a rebellion against the returning Cybermen. When that universe's Mickey dies saving him, Mickey takes his place as the rebellion leader and remains to help the fight.

Rose would be next, the saddest of the departures in this era, seeing as how she and The Doctor had fallen in love over the course of her knowing him. When the Cybermen emerge from their dimension to do battle with the Daleks for the first time in the streets of London, Rose stays on the other side of the dimensional portal to close it up for good, permanently separating her and The Doctor. Just to drive the point further home, when they ARE reunited in The Stolen Earth, The Doctor has to clone himself due to shenanigans, and Rose chooses to be with the clone.

Jack Harkness was never a permanent fixture of The Doctor's crew, so he never officially left. But The Doctor's last gift to him was fixing him up with a cute guy at a bar. Also in the ranks of sorta companions was Sarah Jane Smith, who briefly returned in 10's era, before moving on to her own spinoff show, The Sarah Jane Adventures.

Next on the full companion list was Martha Jones, a young doctor who had an unrequited crush on The Doctor. When she realized that there was no point waiting around for the feelings of a guy who's just gonna run off with the next pretty thing that wanders into his box, she leaves and becomes a badass UNIT agent.

Then we had Donna Noble, a normal woman who briefly met The Doctor during a Christmas special, but had since begun investigating alien occurrences. Her travels with The Doctor came to the most tragic end of all, as after the Daleks infect her memories of The Doctor, he has to wipe her mind of all of their travels so that she can live. Nonetheless, she found her happy ending when she married a poor but sweet artist.

Finally there's Wilfred Mott, Donna's grandfather, who appeared here and there throughout 10's life, slowly becoming more and more influential on his life. In his last adventure, 10 chose to take Wilfred with him, and ultimately embraced the one thing he feared most: his own death and regeneration, in order to save him. We last see Wilfred at Donna's wedding, waving goodbye to The Doctor.